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Bay of Fundy

On a flood tide, 160 billion tonnes of seawater flows into the Bay of Fundy — more than four times the estimated combined flow of all the world’s freshwater rivers during the same 6-hour interval.

The vertical tidal range can be over 16 metres — giving the Bay of Fundy the highest tides in the world. The horizontal range can be as much as 5 kilometres, exposing vast areas of ocean floor.

The tidal currents in the Bay of Fundy are fast, reaching 10 knots (5.1 m/s) at peak surface speed.

Research from California-based Electric Power Research Institute (EPRI) identifies the Bay of Fundy as potentially the best site in North America for tidal power generation, with a world-class resource close to an existing electricity grid.

In the Minas Passage alone, EPRI estimated a nearly 300 megawatt potential (equal to enough power for about 100,000 homes).

More recent research suggests there is more than 7,000 megawatts of potential in the Minas Passage, 2,500 megawatts of which can be extracted without significant effects. Models indicate upwards of 50,000 megawatts of energy exists in the entire Bay of Fundy.

The Guinness Book of World Records states the world’s highest average tides are in the Bay of Fundy, where the mean spring range in the Minas Basin is 14.5 metres (47.6 feet). The highest tide on record in the Bay was 21.6 metres (70.9 feet) in 1869.

Tidal Energy Technology

Design

An in-stream tidal turbine, also called a tidal current turbine, works a lot like an underwater windmill. In-stream technology is designed to use the flow of the tides to turn an impellor, just like a windmill uses the flow of air to turn its blades. Each turbine technology deals with this challenge differently, but each uses the rotation of a turbine to turn an electrical generator.

Some of the technology being explored house the impellors in a shroud or duct, to accelerate the flow of water over the blades, and improve the efficiency of the units. Others are using two reversing pitch propellers, just like a conventional wind turbine, and uses the design of their blades to maximize efficiency.

Operation

The turbines are designed to operate in the open flow of water. In the Minas Passage, they must operate in a range of speeds from zero to 8 knots, depending on where they are sited and how deep they are positioned. Water speed is fastest at the surface and slowest near the sea floor. Tidal power output is very sensitive to water speed, just as windmills are to wind speed. For example, if the water speed doubles, the turbine will produce eight times more power!

Test Centre

FORCE is designed to accommodate three turbines at this time (or up to 5 megawatts in total). Once the underwater cable is installed, the electricity will be transferred to the shore and connected to the Nova Scotia electricity grid.